Fuel pump does not work in Cold Weather, but works fine in warm weather? Will replacing the pump solve this or is there a bad sensor somewhere else causing the problem?
I’d be looking at something else, like the fuel pump relay, before replacing the pump itself.
What’s the temperature at which it stops working?
Usually once it drops below 40F, if it was a bad relay I don’t believe it would work at all, Someone mentioned it could be a Sensor that shuts the fuel pump off in an accident/roll over
Perplexing to say the least, trying to avoid replacing parts that don’t need replaced
The relay was the First thing we Checked, may have to call a ford engineer
How is it determined that the fuel pump is not actually working in this scenario?
What are the symptoms?
One thing I will say at this point is that the only way you are going to talk to a Ford engineer would be if it’s a relative and you see them at a family reunion.
The only response you will get from corporate Ford will be an admonition to “see one of our fine line of quality dealerships with factory trained technicians and the latest in service tools and technology”. True of any car maker.
when it gets below 40F the Fuel pump does not come on when you turn the ignition on, car just turns over is the symptom, once the temps rise fuel pump comes on and car runs fine, did not run all winter, now it’s summer runs like a champ, got multiple theories from various mechanics, they are in agreement it’s not the fuel pump,
You can Hear the fuel pump kick on when you turn the key on, you don’t hear it ( does not come on ) when it’s cold
Further more can’t duplicate now that it is warm out
I had the same issue with my '88 Escort Pony several years ago. When the temperature would get cold overnight many times it would not start first thing in the morning, but as soon as the sun got on the car and it warmed up outside it would start. I think there’s a spring inside the inertia switch and the cold weather was causing it to contract to the point it wasn’t making the correct connection. I went to a junk yard and bought a used inertia switch for $5. and the problem hasn’t returned in the past 15+ years.
Thanks Fordman and Everyone, That is worth looking into!
If your 2000 is like my 97 was, the inertia switch is in the trunk on the passenger side, behind the trunk liner - its very easy to get to. I never had any problems with the switch or the pump, but I used the switch to help depressurize the fuel line (per Haynes manual instructions) whenever I changed the fuel filter by simply disconnecting the switch and starting the car - the fuel pressure quickly drops since the pump isn’t running, allowing easy change of the filter without gas going everywhere.
I’d imagine you could disconnect the switch and use jumpers on the connector to fool the computer into thinking it was connected and the switch was fine… although I don’t know which pins you would want to jump… but that would allow you to diagnose the switch itself…
Thanks Earser, Have a Vortex Tube, I can blast Cold Air on the inertia switch as well, and see if it causes the same symptom, ?
A faulty relay certainly could cause a problem like this, in my opinion at least. Especially one that is over 10 years old. If the inertia switch isn’t causing the trouble I would bet the relay is. Chances are, if you replace both of them you will solve the trouble I would say.
Let us know the results.